# [−][src]Function mynewt::kernel::os::os_mbuf_prepend

    pub unsafe extern "C" fn os_mbuf_prepend(
        om: *mut os_mbuf,
        len: c_int
    ) -> *mut os_mbuf

Increases the length of an mbuf chain by adding data to the front. If there is insufficient room in the leading mbuf, additional mbufs are allocated and prepended as necessary. If this function fails to allocate an mbuf, the entire chain is freed.

The specified mbuf chain does not need to contain a packet header.

- `omp`: The mbuf pool to allocate from.
- `om`: The head of the mbuf chain.
- `len`: The number of bytes to prepend.

Return: The new head of the chain on success; NULL on failure.

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